The continuing development of portable electrically powered devices such as tape recorders and playback machines, radio transmitters and receivers, and the like, creates a continuing demand for the development of reliable, long service life cells or batteries for their operation. Recently developed electrochemical cell systems that will provide a long service life utilize highly reactive anode materials such as lithium, sodium, and the like, in conjunction with high energy density liquid cathode materials and nonaqueous electrolytes. However, the conventional cylindrical cell structures are not ideally suited for the components of these high energy cell systems. For example, in a cylindrical cell, if the anode is disposed in contact with the inner surface of the cell casing and spaced apart a fixed distance from a centrally located cathode or cathode collector by a conventional separator member, then although good contact can be provided between these components when they are assembled in the cell, the contact between these components will decrease as the anode dissolves during discharge. Consequently, the dissolving of the anode during discharge will decrease the volume of the anode and thus tend to increase the distance between anode, separator and cathode or cathode collector thereby increasing the length of the electrolyte path therebetween which will result in an increase of the internal resistance in the cell.
To overcome the above disadvantage when using the components of such high energy density cell systems, it has been proposed that the components be assembled in rolled or coiled electrode assemblies (jelly roll construction) which would ensure good contact between the components of the cell during discharge. This type of cell construction is disclosed in U.S. Pat. No. 3,809,580. Although the jelly roll construction is suitable for liquid and solid cathode cell systems, jelly roll cells are rather expensive to make and time consuming to fabricate and assemble.
U.S. Pat. No. 3,796,606 discloses a cylindrical electrochemical cell whose positive electrode is in contact with the outer casing of the cell and separated by a porous separator from a negative electrode constituted by a sheet of metal having a very negative standard oxidation potential surrounding an elastically deformable current collector having a split cylindrical shape. The elasticity of the current collector enables it to maintain biased contact with the negative electrode at all times notwithstanding alteration in electrode volumes during discharge of the cell and thus to maintain the reacting surfaces of the solid positive and negative electrodes at optimum distances by continuously biasing the negative electrode against the porous separator.
It is an object of this invention to provide a cylindrical type cell employing an inner disposed active metal anode in the form of at least two discrete bodies, such as arcuate or rectangular bodies.
It is another object of the present invention to provide a cylindrical type electrochemical cell employing a liquid or solid active cathode material in conjunction with an active metal anode in the form of at least two discrete arcuate or rectangular bodies.
It is another object of the present invention to provide a nonaqueous cylindrical cell employing a carbonaceous cathode collector, a separator and an inner disposed anode in the form of at least two discrete bodies having resilient biasing means disposed between or within said anode bodies so as to continuously bias the bodies radially outward thereby maintaining the anode, separator and cathode collector of the cell in physical and ionic contact.
It is another object of the present invention to provide cylindrical type cell employing a cathode or cathode collector in conjunction with an inner disposed anode in the form of at least two discrete arcuate bodies having resilient biasing means axially within the space defined by said anode arcuate bodies so that when said arcuate bodies and resilient biasing means are disposed axially within the cylindrical cell, the resilient biasing means will exert a radially outward continuous force so as to maintain the anode, separator and cathode or cathode collector of the cell in physical and ionic contact.
It is another object of the present invention to provide a cylindrical cell employing two semi-cylindrical cathode or cathode collector members in conjunction with at least two discrete rectangular anodes disposed between the semi-cylindrical members and separated from said semi-cylindrical members by a separator and wherein resilient biasing means are employed between the anode members so as to continuously bias said anode members against said separator which in turn contacts the cathode or cathode collector members thereby maintaining these components in physical and ionic contact.
It is another object of the present invention to provide a nonaqueous cylindrical cell having component parts easy to assemble and which will exhibit a relatively low internal cell resistance during discharge.
The foregoing and additional objects will become more fully apparent from the description hereinafter and the accompanying drawings.